Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
  • B01J29/084—Y-type faujasite
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G47/00—Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions
  • C10G47/02—Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions characterised by the catalyst used
  • C10G47/10—Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions characterised by the catalyst used with catalysts deposited on a carrier
  • C10G47/12—Inorganic carriers
  • C10G47/16—Crystalline alumino-silicate carriers
  • C10G47/20—Crystalline alumino-silicate carriers the catalyst containing other metals or compounds thereof

Definitions

• the present invention concerns a catalyst comprising at least one catalytic element and a support comprising at least one 2:1 dioctahedral phyllosilicate containing fluorine, optionally and preferably bridged, at least one matrix and optionally, at least one Y zeolite with a faujasite structure.
• the invention also concerns a process for the hydroconversion of heavy petroleum feeds using this catalyst.
• Hydrocracking of heavy petroleum feeds is a very important refining process which can produce lighter fractions such as gasolines, jet fuels and light gas oils from surplus heavy feeds which are not very valuable, which fractions the refiner needs in order to adapt production to market demands.
• catalytic hydrocracking is intended to provide very high quality middle distillates, jet fuels and gas oils.
• the gasoline produced has a much lower octane number than that from catalytic cracking.
• Catalysts used for hydrocracking are all bifunctional, combining an acid function with a hydrogenating function.
• the acid function is provided by supports with large surface areas (150 to 800 m 2 .g -1 in general) with superficial acidity, such as halogenated aluminas (in particular chlorinated or fluorinated), combinations of boron oxide and aluminium, amorphous silica-aluminas and zeolites.
• the hydrogenating function is provided either by one or a plurality of metals from group VIII of the periodic classification of the elements such as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum, or by a combination of at least one metal from group VI of the periodic classification of the elements such as chromium, molybdenum and tungsten and at least one group VIII metal.
• a weak acid function and a strong hydrogenating function result in catalysts which are of low activity, which operate generally at high temperatures (greater than or equal to 390° C.) and at low space velocities (HSV expressed as the volume of feed to be treated per unit volume of catalyst per hour generally less than or equal to 2) but have very high selectivity towards middle distillates.
• HSV space velocities
• a strong acid function and a weak hydrogenating function produces very active catalysts but with poor selectivity towards middle distillates.
• the correct choice of each of these functions is the problem which must be solved in order to adjust the activity/selectivity couple of the catalyst.
• hydrocracking catalysts are constituted by supports which are weakly acidic, such as amorphous silica-aluminas. Such systems are used to produce very high quality middle distillates and, when the acidity is very low, oil stock.
• Amorphous silica-aluminas are weak acid supports. Many of the hydrocracking catalysts on the market are constituted by silica-alumina associated with either a group VIII metal or, as is preferable when the amount of heteroatomic poisons in the feed exceeds 0.5% by weight, an association of sulphides of metals from groups VIB and VIII. Such systems have very good selectivity towards middle distillates and high quality products are formed. For the most weakly acidic among them, such catalysts can also produce lubricant stock. As already stated, the disadvantage of all of such catalytic systems based on an amorphous support is their low activity.
• a catalyst containing at least one dioctahedral 2:1 phyllosilicate containing fluorine, preferably synthesised in a fluoride medium and preferably bridged, optionally and advantageously combined with a Y zeolite with a faujasite structure can result in substantially improved selectivity towards middle distillates compared with known prior art catalysts.
• Dioctahedral 2:1 phyllosilicates are minerals which are formed by layering elementary sheets. Each sheet comprises two tetrahedral layers located one on each side of an octahedral layer.
• the tetrahedral layer is constituted by ⁇ O 4 tetrahedra, 3 out of 4 vertices being common to 2 tetrahedra and one vertex being free, giving the formula ⁇ O( 3/2+1 ), ⁇ representing a tetrahedral cavity and O representing an oxygen atom.
• the octahedral layer is constituted by ⁇ O 6 octahedra, the 6 vertices being common to 3 octahedra, giving the formula O 6/3 .
• ⁇ represents an octahedral cavity.
• 4 ⁇ 4 O 6+4 tetrahedra are located two by two on each side of 3 ⁇ 3 O 6 octahedra and have 4 vertices in common: ⁇ 4 ⁇ 3O.sub.(12).
• Two O atoms in the octahedral layer do not participate in this sharing and are saturated with H atoms: ⁇ 4 ⁇ 3 O 10 (OH) 2 .
• the tetrahedral cavities ⁇ are usually occupied by silicon atoms and two out of three octahedral cavities ⁇ are occupied by aluminum atoms: Si 4 Al 2 ⁇ O 10 (OH) 2 . This structure is electrically neutral.
• the tetrahedral element silicon can be completely substituted by trivalent elements such as aluminium or gallium.
• the octahedral element aluminium can be substituted by divalent elements (for example Mg or Fe) and/or monovalent elements (for example Li). These substitutions result in an overall negative charge in the structure. This necessitates the existence of exchangeable compensating cations located in the space between the sheets. The thickness of the space between the sheets depends on the nature of the compensating cations and their hydration. This space is also capable of accepting other chemical species such as water, amines, salts, alcohols, bases etc.
• T represents an element selected from group IIIA and iron
• M is at least one compensating cation from the reaction medium or introduced by at least one ion exchange process, selected from the group formed by cations of elements from groups IA, IIA and VIII of the periodic classification of the elements, rare earth cations (cations of elements with atomic number 57 to 71 inclusive), organic cations containing nitrogen (including alkylammonium and arylammonium cations and the ammonium cation), and a proton;
• m is the valency of cation M
• x is a number which is in the range 0 to 2;
• y is a number which is greater than 0 and less than or equal to 2;
• At least one 001 reflection such that d 001 is 12.5 ⁇ 3 ⁇ 10 -10 m depending on the nature of the compensating cation and its hydration at the humidity under consideration.
• the fluorine content is such that the F/Si molar ratio is in the range 0.1 to 4.
• the dioctahedral 2:1 phyllosilicate also has at least one signal at -133 ppm ( ⁇ 5 ppm) in 19 F NMR, with magic angle spinning.
• the phyllosilicates are synthesised in a fluorinated medium in the presence of HF acid and at a pH of less than 9, preferably in the range 0.5 to 6.5.
• the scope of the invention also includes any type of dioctahedral 2:1 phyllosilicate containing fluorine.
• This fluorine can be added on synthesis or after synthesis. Any preparation method is suitable, and that described above is highly advantageous.
• the dioctahedral 2:1 phyllosilicates can be bridged using any technique which is known to the skilled person, in particular the bridging process developed by us and described in patents FR-A-2 720 386 and FR-A-2 720 387, the teachings of which are hereby included by reference.
• This process comprises at least one treatment comprising a first step in which a solution of polycations is brought into contact with the phyllosilicate to be bridged comprising exchangeable cations, to form the reaction mixture; then in a second step, exchange is carried out between the polycations and the exchangeable cations of the phyllosilicate: and finally, in a third step the product obtained is separated by filtering and washed; the treatment is characterized in that:
• the mass of the clay to be bridged per total solution volume is in the range 1 to 200 g/l;
• the second, exchange, step is carried out at a temperature which is in the range 15° C. to 100° C.; said second step has a duration which is in the range 1 minute to 3 hours;
• the separation time in the third step is in the range 20 seconds to 60 minutes per litre of solution containing the product to be separated in suspension.
• This bridging process can simply and rapidly introduce, for example, [A1 13 O 4 (OH) 24 (H 2 O) 12 ] 7+ polycations, also known as Keggin ions, or polycations containing at least one element selected from the group formed by zirconium, titanium, molybdenum and vanadium, non limiting examples of which are: [Zr 4 (OH) 8 (H 2 O) 16 ] 8+ , or [ZrOCl 2 Al 8 (OH) 20 ] 4+ .
• the catalyst of the present invention can also contain a Y zeolite with faujasite structure (Zeolite Molecular Sieves: Structure, Chemistry and Uses, D. W. Breck, J Wiley & Sons, 1973).
• a stabilised Y zeolite is preferably used, which is known as ultrastable zeolite or USY, either in a form which is at least partially exchanged with metal cations, for example alkaline-earth and/or rare earth metal cations with atomic number 57 to 71 inclusive, or in the hydrogen form.
• An acidic zeolite HY is particularly advantageous and is characterised by different specifications: a SiO 2 /Al 2 O 3 molar ratio which is in the range about 8 to 70, preferably in the range 12 to 40; a sodium content of less than 0.15% by weight, determined using zeolite calcined at 1100° C.; a crystal parameter in the unit cell which is in the range 24.55 ⁇ 10 -10 m and 24.24 ⁇ 10 -10 m, preferably in the range 24.38 ⁇ 10 -10 m to 24.26 ⁇ 10 -10 m; a sodium take-up capacity CNa, expressed as the number of grams of Na per 100 grams of modified zeolite, neutralised then calcined, of more than about 0.85; a specific surface area (determined using the B.E.T method) of about 400 m 2 /g, preferably more than 550 m 2 /g, a water vapour adsorption capacity of more than about 6% at 25° C.
• the catalyst of the present invention also contains at least one matrix which is normally amorphous or only slightly crystalline selected, for example, from the group formed by alumina, silica, magnesia, titanium oxide, zirconia, aluminium, titanium or zirconium phosphates, combinations of two or more of these compounds, and alumina-boron oxide combinations.
• the matrix is preferably selected from the group formed by silica, alumina, magnesia, silica-alumina combinations, and silica-magnesia combinations.
• the catalyst support of the present invention thus comprises:
• Y zeolite(s) with faujasite structure in the hydrogen form, preferably with the characteristics given above.
• the catalyst of the present invention can be prepared by any of the methods known to the skilled person.
• a preferred method for use in the present invention consists of grinding a dioctahedral 2:1 phyllosilicate, synthesised in a fluoride medium and optionally bridged, and optionally a Y zeolite, in a wet alumina gel for several tens of minutes, then passing the paste obtained through a die to form extrudates with a diameter which is in the range 0.4 to 4 mm.
• the catalyst also contains at least one catalytic element, for example a metal with a hydro-dehydrogenating function.
• the hydro-dehydrogenating function is provided by at least one metal or compound of a metal from group VIII such as nickel or cobalt.
• a combination of at least one metal or compound of a metal from group VI (in particular molybdenum or tungsten) and at least one metal or compound of a metal from group VIII (in particular cobalt or nickel) of the periodic classification of the elements can be used.
• the total concentration of oxides of metals from groups VI and/or VIII is in the range 1% to 40% by weight of the catalyst, preferably in the range 3% to 30%, advantageously in the range 8% to 40%, more preferably 10% to 40% and most preferably 10% to 30%, and the ratio of the metal(s) from group VI to the metal(s) from general VII is in the range 1.25 to 20, preferably in the range 2 to 10, expressed as the weight of metal oxide.
• the catalyst can contain phosphorous.
• the phosphorous content, expressed as the concentration of phosphorous oxide P 2 O 5 is advantageously less than 15% by weight, preferably less than 10% by weight.
• It can be introduced in part only (for example with combinations of groups VI and VIII) or completely when grinding the dioctahedral 2:1 phyllosilicate synthesised in a fluoride medium and optionally bridged, with a gel of the oxide selected as the matrix. It can be introduced by one of more ion exchange operations carried out on the calcined dioctahedral 2:1 phyllosilicate based support which has been synthesised in a fluoride medium and optionally dispersed in the selected matrix, using solutions containing precursor salts of the selected metals, in particular salts of elements of group VIII.
• It can be introduced by one or more steps for impregnating the formed and calcined support using a solution of precursors of oxides of metals from group VIII (in particular cobalt and nickel) when the precursors of oxides of metals from group VI (in particular molybdenum or tungsten) have already been introduced when grinding the support.
• group VIII in particular cobalt and nickel
• group VI in particular molybdenum or tungsten
• a support based on a dioctahedral 2:1 phyllosilicate synthesised in a fluoride medium and optionally bridged, and a matrix, advantageously already formed and calcined, using one or more solutions containing precursors of oxides of metals of groups VI and/or VIII, precursors of oxides of group VIII metals preferably being introduced after those of group VI or optionally at the same time as the latter.
• an intermediate calcining step is preferably carried out on the catalyst at a temperature which is in the range 250° C. to 600° C.
• Molybdenum impregnation can be facilitated by addition of phosphoric acid to solutions of ammonium paramolybdate.
• the catalysts obtained are used to hydrocrack heavy cuts, and exhibit improved activity over the prior art. In addition, they have improved selectivity towards the production of very high quality middle distillates.
• the feeds used in the process are, for example, gas oils, vacuum distillates, vacuum gas oils, or deasphalted residues or their equivalent.
• Feeds containing high concentrations of N and S preferably have already been hydrotreated.
• at least 80% of their volume is constituted by compounds with boiling points which are at least 350° C., preferably 350° C. to 580° C. (i.e., corresponding to compounds containing at least 15 to 20 carbon atoms). They generally contain heteroatoms such as sulphur and nitrogen.
• the nitrogen content is usually in the range 1 to 5000 ppm by weight and the sulphur content is in the range 0.01% to 5% by weight.
• the hydrocracking conditions such as temperature, pressure, hydrogen recycle ratio, hourly space velocity, can vary widely depending on the nature of the feed, the quality of the desired products, and the installations available to the refiner.
• the temperature is generally more than 230° C., usually in the range 300° C. to 480° C., and preferably less than 450° C.
• the pressure is greater than or equal to 2 MPa, generally more than 3 MPa, up to 10 MPa, and less than 30 MPa.
• the quantity of hydrogen is generally a minimum of 100 l/l of feed, usually in the range 260 to 3000 litres of hydrogen per litre of feed.
• the hourly space velocity is generally between 0.2 and 10 h -1 .
• the factors which are important to the refiner are the activity and selectivity towards middle distillates. Fixed targets must be achieved under conditions which are compatible with economic reality. The refiner thus seeks to reduce the temperature, pressure, and quantity of hydrogen and to maximise the hourly space velocity. Conversion is also known to be increased by raising the temperature, but it is often to the detriment of selectivity. Selectivity towards middle distillates improves with an increase in the pressure or the quantity of hydrogen, but this is to the detriment of the economy of the process.
• This type of catalyst can, under conventional operating conditions, produce selectivities towards middle distillates with boiling points in the range 150° C. to 380° C. of more than 65%, for levels of conversion to products with boiling points of less than 380° C. of more than 55% by volume.
• the selectivities towards middle distillates are over 65% (and generally more than 75%) for levels of conversion of more than 30%, generally around 40-50%, and usually less than 55%. Further, under these conditions, the catalyst has remarkable stability. Finally, because of the composition of the catalyst, it can readily be regenerated.
• composition of the hydrogel thus prepared, with respect to one mole of oxide SiO 2 was:
• This composition did not take into account the water provided by the aluminium source and the HF acid.
• the hydrogel obtained was aged for 4 hours at ambient temperature (20° C.) with moderate stirring.
• the pH was close to 5.
• the pH at the end of the synthesis was 4.
• the product was recovered, filtered and washed with copious quantities of distilled water. It was then dried at 40-50° C. for 24 hours.
• This diffraction spectrum was characteristic of that of the dioctahedral 2:1 phyllosilicates of the invention.
• the fluorine content of the phyllosilicate obtained was 3.15%.
• the dioctahedral 2:1 phyllosilicate prepared was designated P1. This latter then underwent a bridging step using the operating procedure described below.
• the mass of clay to be bridged per total solution volume was thus 54 g/l.
• the ratio R defined as the ratio between the quantity of polycations engaged multiplied by the charge on the polycation and the quantity of sodium present in the beidellite, was 1.
• the product was washed with distilled water for 2 minutes, then dried overnight at 90° C. (about 15 hours).
• the mass of bridged phyllosilicate after ion exchange and drying at 60° C. was 0.85 g.
• the reticular spacing d 001 was of the order of 1.92 nm and the specific surface area measured using the BET method was of the order of 265 m 2 /g.
• the bridged clay had a reticular spacing dool of the order of 1.83 nm and a BET specific surface area of 230 m 2 /g.
• Dioctahedral 2:1 phyllosilicate PP1 described in Example 1 was ground with SB3 type alumina provided by Condea.
• the ground paste was extruded through a 1.4 mm diameter die.
• the extrudates were dry impregnated with a solution of a mixture of ammonium heptamolybdate, nickel nitrate and orthophosphoric acid, and finally calcined in air at 550° C. in-situ in the reactor in which they were in the form of a fixed bed.
• the active oxide contents were as follows (by weight with respect to catalyst):
• the bridged clay content in the catalyst ensemble was 40%.
• Dioctahedral 2:1 phyllosilicate PP1 described in Example 1 and an HY zeolite with a lattice parameter of 24.30 ⁇ were ground with SB3 type alumina provided by Condea.
• the ground paste was extruded through a 1.4 mm diameter die.
• the extrudates were dry impregnated with a solution of a mixture of ammonium heptamolybdate, nickel nitrate and orthophosphoric acid, and finally calcined in air at 550° C. in-situ in the reactor in which they were in the form of a fixed bed.
• the active oxide contents were as follows (by weight with respect to catalyst):
• the bridged clay content in the catalyst ensemble was 35%, and the HY zeolite content was 5% by weight.
• a laboratory prepared silica-alumina containing 25% by weight of SiO 2 and 75% by weight of Al 2 O 3 was used. 3% by weight of pure nitric acid was added to 67% with respect to the dry weight of the silica-alumina powder to peptise the powder. After grinding, the paste obtained was extruded through a 1.4 mm diameter die. The extrudates were calcined then dry impregnated with a solution of a platinum tetramine chloride salt Pt(NH 3 ) 4 Cl 2 and finally calcined in air at 550° C. The platinum content in the final catalyst was 0.6% by weight.
• Catalysts C1 and C2 prepared as above were used under hydrocracking conditions with a petroleum cut with the following principal characteristics:
• the catalytic test unit comprised a fixed bed reactor, in up-flow mode, into which 80 ml of catalyst was introduced. Each catalyst was sulphurized with a n-hexane/DMDS+aniline mixture up to 320° C. The total pressure was 9 MPa, the hydrogen flow rate was 1000 litres of hydrogen gas per litre of injected feed, and the hourly space velocity was 1.0 h -1 .
• Catalytic performances were expressed as the temperature for 70% gross conversion and by the gross selectivity. These catalytic performances were measured for the catalyst after a stabilisation period which was generally at least 48 hours.
• the gross selectivity GS was taken as:
• selectivity varies greatly with conversion. Selectivity increases as conversion decreases.
• the use of such a bridged dioctahedral 2:1 phyllosilicate thus produces a substantial gain in the iso-conversion temperature without detriment to the selectivity towards middle distillates.
• Catalysts C1 and C3 were compared in a low pressure hydrocracking test, also known as mild hydrocracking.
• the feed used during the catalytic test was the same as that used in Example 5.
• the catalytic test unit comprised a fixed bed reactor, in up-flow mode, into which 80 mnl of catalyst was introduced. Each catalyst was sulphurized with a n-hexane/DMDS+aniline mixture up to 320° C. The total pressure was 5 MPa, the hydrogen flow rate was 500 litres of hydrogen gas per litre of injected feed, and the hourly space velocity was 0.5 h -1 .
• Catalytic performances were expressed as the gross conversion obtained at a given temperature (in this case, 400° C.) and by the gross selectivity for a gross conversion of 50%. These catalytic performances were measured for the catalyst after a stabilisation period which was generally at least 48 hours.

Landscapes

• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Materials Engineering (AREA)
• Inorganic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Catalysts (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=26232553

Family Applications (1)

Country Status (3)

Cited By (8)

Families Citing this family (1)

Citations (10)

Family Cites Families (1)

• 1996
  • 1996-02-27 FR FR9602533A patent/FR2745203B1/fr not_active Expired - Fee Related
• 1997
  • 1997-02-24 EP EP97400404A patent/EP0792686A1/fr not_active Ceased
  • 1997-02-26 US US08/806,672 patent/US5997725A/en not_active Expired - Fee Related

Patent Citations (10)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events